Printed circuit multiple connector block



Nov. 26, 1963 R. c. SWENGEL PRINTED CIRCUIT MULTIPLE CONNECTOR BLOCK 2Sheets-Sheet 1 Original Filed Feb. 11', 1957 INVENTOR. Roam-r C.SQENGEL.

Nov. 26, 1963 R. c. SWENGEL PRINTED CIRCUIT MULTIPLE CONNECTOR BLOCK 2Sheets-Sheet 2 Original Filed Feb. 11, 1957 INVENTOR. Qaeam C Swansea.

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km z/ United States Patent 3,112,145 PRINTED CIRCUIT MULTEPLE CONNECTGRBLOCK Robert C. Swengel, Hellam, Pa, assignor to AMP Incorporated,Harrisburg, Pa.

Original application Feb. 11, 1957, Ser. No. 639,461, now Patent No.2,980,878, dated Apr. 18, 1361. Divided and this application June 22,1960, Ser. No. 46,855

1 Claim. (Cl. 339-17) This invention relates to printed circuitconnections and more particularly to an improved printed circuit boardor panel and terminal clips cooperable therewith for making connectionsbetween the electrical network defined by the printed circuit board andelectrical circuitry external to the printed circuit board. Thisapplication is a division of my copending application, Serial No.639,461, filed February 11, 1957, now Patent No. 2,980,- 878, issuedApril 18, 1961.

As used herein, the term printed circuit board includes a supportingbase or body of any suitable insulating material on which the electricalwiring of an electronic circuit is reproduced by any suitable processsuch as chemical deposition, die stamping, painting, etc. The circuitdesign may encompass both sides of the panel and may be printed with orwithout other circuit parameters such as resistors, capacitors, etc.,the wiring usually taking the form of extremely thin and narrow stripsor ribbons of electrically conductive material such as copper, silver,or tin, or a combination thereof.

It is an object of the present invention to provide electricalconnections with printed circuit boards which are simple in constructionand in installation and inexpensive to produce;

Another object is to provide a printed circuit connection for externalwiring which may readily be disconnected for disassociating the printedcircuit unit from the remainder of the system;

Another object of the present invention is to provide a printed circuitpanel connection wherein an external lead wire is directly coupled tothe printed circuit conductive ribbons through a single solderlessterminal part;

Still another object is to provide in a friction fit connection forprinted circuit panels, connector parts which are self-cleansing,require low connective forces, but result in high contact pressures overthe contact areas without damage to the conductive ribbons of theprinted circuit panel;

Still another object is to provide in a frictional fit connection forprinted circuit panels, a terminal clip sufficiently resilient to acceptwide variations in thickness of the insulation body and to overcomeplastic creep of the insulation under load;

A still further object is to provide in a frictional fit connection forprinted circuit panels a terminal clip which promotes the circulation ofair for ventilation purposes and avoids entrapment of moisture or otherforeign matter within the connector parts;

A still further object is to provide in a friction fit connection forprinted circuit panels a terminal clip which is mechanically stableunder vibration or externally imposed stresses on the lead-in wires.

In general these and other objectives are attained in accordance withthe present invention by providing in a printed circuit panel aplurality of slots which extend inwardly from one or more of the sideedges of the panel, the number of slots corresponding to the number ofexternal connections desired. Incorporated within the circuit designprinted on the panel are a number of conductive ribbons leading from theinput and output junctions of the circuitry involved, which ribbonsextend to the panel side edges along and adjacent appropriate slots.

ICC

These slots are adapted to receive a sheet metal terminal which includesa coupling portion adapted for solderlcss connection to electricalcircuitry, such as a lead-in wire external of the panel, and a clipportion which comprises a base and resilient spring elements extendingfrom the base, for example a pair of lateral arms extending fromopposite sides of and turned back upon the base. In connection the clipbase is received within an appropriate panel slot with the end edges ofthe spring arms gripping the panel resiliently therebetween with atleast one of the end edges bearing upon an adjacent lead ribbon.

Other objects and attainments of the present invention will becomeapparent to those skilled in the art upon a reading of the followingdetailed description when taken in conjunction with the drawings inwhich there are shown and described illustrative embodiments of theinvention; it is to be understood however that these embodiments are notintended to be exhaustive nor limiting on the scope of the invention butare given for purposes of illustration in order that others skilled inthe art may fully understand the invention and the principles thereofand the manner of applying it in practical use so that they may modifyit in various forms each as may be best suited to the conditions of aparticular use.

In the drawings:

FIGURE 1 is a fragmentary view in perspective of a printed circuit boardhaving connections made in accordance with the present invention;

FIGURE 2 is a sectional view taken along lines 2-2 of FIGURE 1;

FIGURE 3 is a plan view of a connector for making one of the connectionsshown in FIGURE 1;

FIGURE 4 is a fragmentary view in perspective of a strip of sheet metalelectrical terminals for making one of the connections shown in FIGURE1, the terminals being adapted for application to lead wires byautomatic or semi-automatic crimping machines;

FIGURE 5 is a sectional view of a further embodiment of the printedcircuit board connection according to the present invention;

FIGURE 6 is a view in perspective of a terminal block using the printedcircuit connections of the present invention;

FIGURE 7 is a plan view of the terminal block of FIGURE 6 with partsbroken away for purposes of illustration;

FIGURE 8 is a sectional view taken along lines 88 of FIGURE 7.

Referring now to FIGURE 1, a printed circuit board panel or body 2 ofsuitable insulation material has reproduced thereon a circuit pattern ordesign including a plurality of thin narrow strips or ribbons 4 ofconductive material which represent the intercomponent 'wiring of anelectronic assembly. The ends 6 of some of strips 4 terminate atapertures '8 into which the leads of components, not shown, such asresistors, coils, tubes, etc., are inserted and then soldered, all as isconventional in the art. The printed circuit design may be composed ofstrips 4 on either, or as is the usual case, on both sides of panel 2,the connection of my invention being applicable in either case.

The segments or strip ends 10 which constitute the input and outputleads of the circuit defined by strips 4 are brought, in accordance withthe present invention, to any side edge 12 of panel 2-, and, for reasonsto become apparent, preferably are widened to several times theapproximate 0.025 inch strip width usually suflicient for strips 4.Extending inwardly of side edge 12 adjacent and along strip ends 10respectively are a plurality of slots 14, each being adapted to receivein electrical connection with the associated strip end It a terminal 16attached to the end of an external lead 18. By bringing strip ends tovarious edges of the board, it will be apparent that like connectionsmay be made on any side of panel 2 although, as is shown in FIGURE 1,all connections are conveniently made in practice along one side edge12. The connection aflForded by terminal 16 thus serves to coupleexternal lead wire :18 to the desired input or output strip end 10, anydesired number of such connections being provided, corresponding, forexample, to the number of input or output leads required to completeincorporation of the circuit of the printed circuit board within theelectrical equipment involved.

Terminal 16, of suitably resilient sheet metal such as No. 4 hard brass,includes a clip portion 20, FIGURE 3, for contacting strip ends 10, anda coupling portion 22 integrally connected to clip 20 by transitionsection 24, coupling portion 22 being adapted to afiix the terminalelectrically and mechanically to lead Wire 18 as generally indicated inFIGURES 1 and 3. With additional reference to FIGURES 2 and 4, clip 20comprises a generally rectangular base 26 adapted to be slipped within aslot 14 at right angles to panel 2, and opposed spring arms 28 extendingfrom opposite sides of and turned back upon base 26 to determine inlongitudinally directed linear end edges 30 spaced to engage resilientlythe upper and lower faces of panel 2, FIGURE 2. More particularly, arms28 are turned back upon base 26 about radii of curvature as large aspossible to avoid concentration of stresses during flexure, and extendlinearly thereafter outwardly from base 26 to form therewith anopen-ended channel for receiving an edge portion of panel 2 as definedby one side of a slot 14. Edges 30, however, are spaced less than anyanticipated thickness of panel 2 so that on assembling the connection,these edges forcibly bear on the opposed surfaces of the board and onthe conductive strips with which the slot is associated.

In general coupling portion 22 may take a variety of forms but issolderless in nature, that is, a ferrule-forming part adapted to be coldcrimped onto the end of lead wire 18 by solderless techniques well knownin the art. Such a ferrule typically includes, FIGURE 4, a U-shapedportion having first upstanding ears 32. adapted for turning inwardlyand downwardly upon the exposed metallic core of lead 18 and a secondpair of ears 34 which are formed about the insulation, if any, of thelead in the crimping process. Alternatively, coupling portion 22 may beomitted where the function to be served is to couple opposed strips onthe upper and lower surfaces of the board. Transition section 24 servesto reduce the wider clip portion to the width of coupling portion 22 andis flanged at edges 36 to lend rigidity to the construction.

It will be apparent that terminal 16 may be formed from sheet metal byconventional blanking and shaping techniques well known in the art,conveniently in strip form, that is, a string of terminals wherein eachterminal is joined to others either in end-to-end fashion, FIGURE 4, orin ladder form, not shown. When thus formed the terminals may be woundin reels for application to leads 18 by automatic or semi-automaticcrimping machines.

With coupling portion 22 crimped onto the end of lead wire 18, insertionof clip base 26 within a slot '14 and introduction of an edge portion ofthe board within the channel defined by the clip cause resilient springarms 26 to be wedged open and end edges 30 to be brought into forcefulengagement with strip ends 10 thereby providing the desired solderlessconnection between lead wire 18 and printed circuit strips 4. Tofacilitate application of base 26 to the appropriate slot 14- theforward corners 38 of arms 28 are chamfered or bevelled so as to curveaway from the insertion end of the clip thus to produce initially asmooth camming action for distending the spring arms. In addition thewidth of slot 14 will, of course, be wider than the thickness of base 26to provide a target area of suitable scope for facile indexing of theclip base. The slot width, however, should not be so great as to permitexcessive lateral play 4- of the clip which should be stabilized inposition as will be described. For reasons to become more apparent theslot width advantageously approximates twice the thick ness of the sheetmetal forming clip 20.

Electrical continuity between clip 20 and a strip 4 will be seen to be aline contact afforded by end edges 39 hearing on strip ends 10. To avoiddamaging the relatively delicate printed circuit strips, typically ofthe order of .001 inch in thickness, inside corners 40 of end edges 30are rounded as best shown in the enlarged cross sectional view of FIGURE5.

In making the connection, as the clip is slipped into position, therelatively harder metal of the clip is caused at end edges 30 forcefullyto bear on a very limited area of the softer metal of the printedcircuit strips, commonly a base of copper overlaid with tin. Because ofthe small area of contact even relatively small distensions of the clipspring arms result in relatively high contact pressures that deform andslightly groove the metal of the strips as end edges 30 progresstherealong. Rounded corners 40, however, effectively increase thebearing surface sufficiently to prevent shearing of the conductivestrips. Advantageously, the burnishing and grooving action removes anyforeign material while exposing fresh metal at the contact surfaces.This selfcleansing action may be enhanced by forming a slightconvergence in edges 30 toward the forward or insertion end of the clip,as indicated in FIGURE 3. The increased contact pressure, resulting froma greater deflection of the spring arms, assures an effectively scrubbedline of contact for subsequent engagement by the more rearwardlyportions of the spring arms. In this connection in view of the widerwidth of slot .14 as compared to the sheet metal thickness of base 26,to prevent shifting of the clip off the established clean line ofcontact on strip end 10, bosses 42 are preferably raised out of thesection of base 26 residing within the board thickness to a height whichincreases the effective thickness of the base to the width of the slot,as best shown in FIGURE 2. Bosses 42, however, should be disposedsufficiently back from the insertion end of the clip so as not tointerfere with the indexing of base 26 to the desired slot 14.

FIGURE 5 also illustrates incorporation in base a strain relief toprevent overstressing of the spring arms of the clip. As shown, a pairof opposed tabs 76 are struck inwardly of base 80, the ends of the tabsspaced apart approximately equal to the width or thickness of theprinted circuit board. Tabs 76 are short and relatively rigid ascompared to spring arms 28 and thus act to absorb any stresses imposedon the terminal upon receiving the panel therebetween.

In FIGURES 6, 7 and 8, printed wiring panel is shown generallyrectangular in form and elongated to comprise the connective element ofa terminal block arrangement, printed circuit strips 92 extending fromassociated terminal receiving slots 94 on one long side 96 in anydesired pattern or design to the other long side 98 of panel 90. In theillustrated embodiment conductive strips 92 lead directly from theseries of slots on one side of panel 90 to respectively opposed slots onthe opposite side to provide a series of straight-through connections,for example between terminal 100 on side 96 to terminal 102 on side 98of the block. In this connection by omitting any space take-up bosses 42in the base of the terminal clip portion and arranging slots 94 to becentrally disposed in a wider printed circuit strip, a pair of terminals100 and 104 may be disposed base-to-base, or back-toback within a singleslot, as shown in FIGURES 7 and 8, each strip thus serving as afour-wire common bus. It will be understood, however, that in general bysuitably printing strips 92 on either one or both faces of panel 90, aterminal on one side of the board may be connected to any desired numberof terminals on either the opposite or same side of the terminal block.Cover plates 108 of insulation material, spatially disposed by spacerblocks 110 and secured relative to panel 90 by eyelets or rivets 112,may be added if desired.

I claim:

A multiple electrical connector comprising a terminal block including aprinted circuit board having conductive ribbons extending in paralleluninterrupted continuity across at least one face of the board andterminating at two opposite side edges of the board, slots extendinginwardly of said side edges centrally in said ribbons respectively, aplurality of spring clip terminals each having a spring member and acrimp portion fastened onto an individual flexible Wire conductor, saidterminals being slidably disposed in said slots with the spring membersresiliently bearing upon said ribbons respectively, each slot having aWidth to receive a pair of terminals for contact with one end of aconductive ribbon on either side of the slot, each conductive ribbondirectly connecting a pair of said terminals and associated conductorsdisposed at said side edges respectively.

References Cited in the file of this patent UNITED STATES PATENTS1,302,137 Cook Apr. 29, 1919 2,707,272 Blitz Apr. 26, 1955 2,789,278Soreng Apr. 16, 1957 2,927,251 Jones Mar. 1, 1960 2,931,003 Huetten eta1. Mar. 29, 1960 FOREIGN PATENTS 1,086,548 France Aug. 11, 1954 OTHERREFERENCES AMP Electronic Design, Nov. 15, 1956, page 17.

